/**
   * include/linux/f2fs_fs.h
   *
   * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   *             http://www.samsung.com/
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #ifndef _LINUX_F2FS_FS_H
  #define _LINUX_F2FS_FS_H
  
  #include <linux/pagemap.h>
  #include <linux/types.h>
  
  #define F2FS_SUPER_OFFSET		1024	/* byte-size offset */
  #define F2FS_LOG_SECTOR_SIZE		9	/* 9 bits for 512 byte */
  #define F2FS_LOG_SECTORS_PER_BLOCK	3	/* 4KB: F2FS_BLKSIZE */
  #define F2FS_BLKSIZE			4096	/* support only 4KB block */
  #define F2FS_MAX_EXTENSION		64	/* # of extension entries */
  
  #define NULL_ADDR		((block_t)0)	/* used as block_t addresses */
  #define NEW_ADDR		((block_t)-1)	/* used as block_t addresses */
  
  #define F2FS_ROOT_INO(sbi)	(sbi->root_ino_num)
  #define F2FS_NODE_INO(sbi)	(sbi->node_ino_num)
  #define F2FS_META_INO(sbi)	(sbi->meta_ino_num)
  
  /* This flag is used by node and meta inodes, and by recovery */
  #define GFP_F2FS_ZERO	(GFP_NOFS | __GFP_ZERO)
  
  /*
   * For further optimization on multi-head logs, on-disk layout supports maximum
   * 16 logs by default. The number, 16, is expected to cover all the cases
   * enoughly. The implementaion currently uses no more than 6 logs.
   * Half the logs are used for nodes, and the other half are used for data.
   */
  #define MAX_ACTIVE_LOGS	16
  #define MAX_ACTIVE_NODE_LOGS	8
  #define MAX_ACTIVE_DATA_LOGS	8
  
  /*
   * For superblock
   */
  struct f2fs_super_block {
  	__le32 magic;			/* Magic Number */
  	__le16 major_ver;		/* Major Version */
  	__le16 minor_ver;		/* Minor Version */
  	__le32 log_sectorsize;		/* log2 sector size in bytes */
  	__le32 log_sectors_per_block;	/* log2 # of sectors per block */
  	__le32 log_blocksize;		/* log2 block size in bytes */
  	__le32 log_blocks_per_seg;	/* log2 # of blocks per segment */
  	__le32 segs_per_sec;		/* # of segments per section */
  	__le32 secs_per_zone;		/* # of sections per zone */
  	__le32 checksum_offset;		/* checksum offset inside super block */
  	__le64 block_count;		/* total # of user blocks */
  	__le32 section_count;		/* total # of sections */
  	__le32 segment_count;		/* total # of segments */
  	__le32 segment_count_ckpt;	/* # of segments for checkpoint */
  	__le32 segment_count_sit;	/* # of segments for SIT */
  	__le32 segment_count_nat;	/* # of segments for NAT */
  	__le32 segment_count_ssa;	/* # of segments for SSA */
  	__le32 segment_count_main;	/* # of segments for main area */
  	__le32 segment0_blkaddr;	/* start block address of segment 0 */
  	__le32 cp_blkaddr;		/* start block address of checkpoint */
  	__le32 sit_blkaddr;		/* start block address of SIT */
  	__le32 nat_blkaddr;		/* start block address of NAT */
  	__le32 ssa_blkaddr;		/* start block address of SSA */
  	__le32 main_blkaddr;		/* start block address of main area */
  	__le32 root_ino;		/* root inode number */
  	__le32 node_ino;		/* node inode number */
  	__le32 meta_ino;		/* meta inode number */
  	__u8 uuid[16];			/* 128-bit uuid for volume */
  	__le16 volume_name[512];	/* volume name */
  	__le32 extension_count;		/* # of extensions below */
  	__u8 extension_list[F2FS_MAX_EXTENSION][8];	/* extension array */
  } __packed;
  
  /*
   * For checkpoint
   */
  #define CP_ERROR_FLAG		0x00000008
  #define CP_COMPACT_SUM_FLAG	0x00000004
  #define CP_ORPHAN_PRESENT_FLAG	0x00000002
  #define CP_UMOUNT_FLAG		0x00000001
  
  struct f2fs_checkpoint {
  	__le64 checkpoint_ver;		/* checkpoint block version number */
  	__le64 user_block_count;	/* # of user blocks */
  	__le64 valid_block_count;	/* # of valid blocks in main area */
  	__le32 rsvd_segment_count;	/* # of reserved segments for gc */
  	__le32 overprov_segment_count;	/* # of overprovision segments */
  	__le32 free_segment_count;	/* # of free segments in main area */
  
  	/* information of current node segments */
  	__le32 cur_node_segno[MAX_ACTIVE_NODE_LOGS];
  	__le16 cur_node_blkoff[MAX_ACTIVE_NODE_LOGS];
  	/* information of current data segments */
  	__le32 cur_data_segno[MAX_ACTIVE_DATA_LOGS];
  	__le16 cur_data_blkoff[MAX_ACTIVE_DATA_LOGS];
  	__le32 ckpt_flags;		/* Flags : umount and journal_present */
  	__le32 cp_pack_total_block_count;	/* total # of one cp pack */
  	__le32 cp_pack_start_sum;	/* start block number of data summary */
  	__le32 valid_node_count;	/* Total number of valid nodes */
  	__le32 valid_inode_count;	/* Total number of valid inodes */
  	__le32 next_free_nid;		/* Next free node number */
  	__le32 sit_ver_bitmap_bytesize;	/* Default value 64 */
  	__le32 nat_ver_bitmap_bytesize; /* Default value 256 */
  	__le32 checksum_offset;		/* checksum offset inside cp block */
  	__le64 elapsed_time;		/* mounted time */
  	/* allocation type of current segment */
  	unsigned char alloc_type[MAX_ACTIVE_LOGS];
  
  	/* SIT and NAT version bitmap */
  	unsigned char sit_nat_version_bitmap[1];
  } __packed;
  
  /*
   * For orphan inode management
   */
  #define F2FS_ORPHANS_PER_BLOCK	1020
  
  struct f2fs_orphan_block {
  	__le32 ino[F2FS_ORPHANS_PER_BLOCK];	/* inode numbers */
  	__le32 reserved;	/* reserved */
  	__le16 blk_addr;	/* block index in current CP */
  	__le16 blk_count;	/* Number of orphan inode blocks in CP */
  	__le32 entry_count;	/* Total number of orphan nodes in current CP */
  	__le32 check_sum;	/* CRC32 for orphan inode block */
  } __packed;
  
  /*
   * For NODE structure
   */
  struct f2fs_extent {
  	__le32 fofs;		/* start file offset of the extent */
  	__le32 blk_addr;	/* start block address of the extent */
  	__le32 len;		/* lengh of the extent */
  } __packed;
  
  #define F2FS_NAME_LEN		255
  #define F2FS_INLINE_XATTR_ADDRS	50	/* 200 bytes for inline xattrs */
  #define DEF_ADDRS_PER_INODE	923	/* Address Pointers in an Inode */
  #define ADDRS_PER_INODE(fi)	addrs_per_inode(fi)
  #define ADDRS_PER_BLOCK		1018	/* Address Pointers in a Direct Block */
  #define NIDS_PER_BLOCK		1018	/* Node IDs in an Indirect Block */
  
  #define	NODE_DIR1_BLOCK		(DEF_ADDRS_PER_INODE + 1)
  #define	NODE_DIR2_BLOCK		(DEF_ADDRS_PER_INODE + 2)
  #define	NODE_IND1_BLOCK		(DEF_ADDRS_PER_INODE + 3)
  #define	NODE_IND2_BLOCK		(DEF_ADDRS_PER_INODE + 4)
  #define	NODE_DIND_BLOCK		(DEF_ADDRS_PER_INODE + 5)
  
  #define F2FS_INLINE_XATTR	0x01	/* file inline xattr flag */
  #define F2FS_INLINE_DATA	0x02	/* file inline data flag */
  
  #define MAX_INLINE_DATA		(sizeof(__le32) * (DEF_ADDRS_PER_INODE - \
  						F2FS_INLINE_XATTR_ADDRS - 1))
  
  #define INLINE_DATA_OFFSET	(PAGE_CACHE_SIZE - sizeof(struct node_footer) \
  			- sizeof(__le32) * (DEF_ADDRS_PER_INODE + 5 - 1))
  
  struct f2fs_inode {
  	__le16 i_mode;			/* file mode */
  	__u8 i_advise;			/* file hints */
  	__u8 i_inline;			/* file inline flags */
  	__le32 i_uid;			/* user ID */
  	__le32 i_gid;			/* group ID */
  	__le32 i_links;			/* links count */
  	__le64 i_size;			/* file size in bytes */
  	__le64 i_blocks;		/* file size in blocks */
  	__le64 i_atime;			/* access time */
  	__le64 i_ctime;			/* change time */
  	__le64 i_mtime;			/* modification time */
  	__le32 i_atime_nsec;		/* access time in nano scale */
  	__le32 i_ctime_nsec;		/* change time in nano scale */
  	__le32 i_mtime_nsec;		/* modification time in nano scale */
  	__le32 i_generation;		/* file version (for NFS) */
  	__le32 i_current_depth;		/* only for directory depth */
  	__le32 i_xattr_nid;		/* nid to save xattr */
  	__le32 i_flags;			/* file attributes */
  	__le32 i_pino;			/* parent inode number */
  	__le32 i_namelen;		/* file name length */
  	__u8 i_name[F2FS_NAME_LEN];	/* file name for SPOR */
  	__u8 i_reserved2;		/* for backward compatibility */
  
  	struct f2fs_extent i_ext;	/* caching a largest extent */
  
  	__le32 i_addr[DEF_ADDRS_PER_INODE];	/* Pointers to data blocks */
  
  	__le32 i_nid[5];		/* direct(2), indirect(2),
  						double_indirect(1) node id */
  } __packed;
  
  struct direct_node {
  	__le32 addr[ADDRS_PER_BLOCK];	/* array of data block address */
  } __packed;
  
  struct indirect_node {
  	__le32 nid[NIDS_PER_BLOCK];	/* array of data block address */
  } __packed;
  
  enum {
  	COLD_BIT_SHIFT = 0,
  	FSYNC_BIT_SHIFT,
  	DENT_BIT_SHIFT,
  	OFFSET_BIT_SHIFT
  };
  
  struct node_footer {
  	__le32 nid;		/* node id */
  	__le32 ino;		/* inode nunmber */
  	__le32 flag;		/* include cold/fsync/dentry marks and offset */
  	__le64 cp_ver;		/* checkpoint version */
  	__le32 next_blkaddr;	/* next node page block address */
  } __packed;
  
  struct f2fs_node {
  	/* can be one of three types: inode, direct, and indirect types */
  	union {
  		struct f2fs_inode i;
  		struct direct_node dn;
  		struct indirect_node in;
  	};
  	struct node_footer footer;
  } __packed;
  
  /*
   * For NAT entries
   */
  #define NAT_ENTRY_PER_BLOCK (PAGE_CACHE_SIZE / sizeof(struct f2fs_nat_entry))
  
  struct f2fs_nat_entry {
  	__u8 version;		/* latest version of cached nat entry */
  	__le32 ino;		/* inode number */
  	__le32 block_addr;	/* block address */
  } __packed;
  
  struct f2fs_nat_block {
  	struct f2fs_nat_entry entries[NAT_ENTRY_PER_BLOCK];
  } __packed;
  
  /*
   * For SIT entries
   *
   * Each segment is 2MB in size by default so that a bitmap for validity of
   * there-in blocks should occupy 64 bytes, 512 bits.
   * Not allow to change this.
   */
  #define SIT_VBLOCK_MAP_SIZE 64
  #define SIT_ENTRY_PER_BLOCK (PAGE_CACHE_SIZE / sizeof(struct f2fs_sit_entry))
  
  /*
   * Note that f2fs_sit_entry->vblocks has the following bit-field information.
   * [15:10] : allocation type such as CURSEG_XXXX_TYPE
   * [9:0] : valid block count
   */
  #define SIT_VBLOCKS_SHIFT	10
  #define SIT_VBLOCKS_MASK	((1 << SIT_VBLOCKS_SHIFT) - 1)
  #define GET_SIT_VBLOCKS(raw_sit)				\
  	(le16_to_cpu((raw_sit)->vblocks) & SIT_VBLOCKS_MASK)
  #define GET_SIT_TYPE(raw_sit)					\
  	((le16_to_cpu((raw_sit)->vblocks) & ~SIT_VBLOCKS_MASK)	\
  	 >> SIT_VBLOCKS_SHIFT)
  
  struct f2fs_sit_entry {
  	__le16 vblocks;				/* reference above */
  	__u8 valid_map[SIT_VBLOCK_MAP_SIZE];	/* bitmap for valid blocks */
  	__le64 mtime;				/* segment age for cleaning */
  } __packed;
  
  struct f2fs_sit_block {
  	struct f2fs_sit_entry entries[SIT_ENTRY_PER_BLOCK];
  } __packed;
  
  /*
   * For segment summary
   *
   * One summary block contains exactly 512 summary entries, which represents
   * exactly 2MB segment by default. Not allow to change the basic units.
   *
   * NOTE: For initializing fields, you must use set_summary
   *
   * - If data page, nid represents dnode's nid
   * - If node page, nid represents the node page's nid.
   *
   * The ofs_in_node is used by only data page. It represents offset
   * from node's page's beginning to get a data block address.
   * ex) data_blkaddr = (block_t)(nodepage_start_address + ofs_in_node)
   */
  #define ENTRIES_IN_SUM		512
  #define	SUMMARY_SIZE		(7)	/* sizeof(struct summary) */
  #define	SUM_FOOTER_SIZE		(5)	/* sizeof(struct summary_footer) */
  #define SUM_ENTRY_SIZE		(SUMMARY_SIZE * ENTRIES_IN_SUM)
  
  /* a summary entry for a 4KB-sized block in a segment */
  struct f2fs_summary {
  	__le32 nid;		/* parent node id */
  	union {
  		__u8 reserved[3];
  		struct {
  			__u8 version;		/* node version number */
  			__le16 ofs_in_node;	/* block index in parent node */
  		} __packed;
  	};
  } __packed;
  
  /* summary block type, node or data, is stored to the summary_footer */
  #define SUM_TYPE_NODE		(1)
  #define SUM_TYPE_DATA		(0)
  
  struct summary_footer {
  	unsigned char entry_type;	/* SUM_TYPE_XXX */
  	__u32 check_sum;		/* summary checksum */
  } __packed;
  
  #define SUM_JOURNAL_SIZE	(F2FS_BLKSIZE - SUM_FOOTER_SIZE -\
  				SUM_ENTRY_SIZE)
  #define NAT_JOURNAL_ENTRIES	((SUM_JOURNAL_SIZE - 2) /\
  				sizeof(struct nat_journal_entry))
  #define NAT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\
  				sizeof(struct nat_journal_entry))
  #define SIT_JOURNAL_ENTRIES	((SUM_JOURNAL_SIZE - 2) /\
  				sizeof(struct sit_journal_entry))
  #define SIT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\
  				sizeof(struct sit_journal_entry))
  /*
   * frequently updated NAT/SIT entries can be stored in the spare area in
   * summary blocks
   */
  enum {
  	NAT_JOURNAL = 0,
  	SIT_JOURNAL
  };
  
  struct nat_journal_entry {
  	__le32 nid;
  	struct f2fs_nat_entry ne;
  } __packed;
  
  struct nat_journal {
  	struct nat_journal_entry entries[NAT_JOURNAL_ENTRIES];
  	__u8 reserved[NAT_JOURNAL_RESERVED];
  } __packed;
  
  struct sit_journal_entry {
  	__le32 segno;
  	struct f2fs_sit_entry se;
  } __packed;
  
  struct sit_journal {
  	struct sit_journal_entry entries[SIT_JOURNAL_ENTRIES];
  	__u8 reserved[SIT_JOURNAL_RESERVED];
  } __packed;
  
  /* 4KB-sized summary block structure */
  struct f2fs_summary_block {
  	struct f2fs_summary entries[ENTRIES_IN_SUM];
  	union {
  		__le16 n_nats;
  		__le16 n_sits;
  	};
  	/* spare area is used by NAT or SIT journals */
  	union {
  		struct nat_journal nat_j;
  		struct sit_journal sit_j;
  	};
  	struct summary_footer footer;
  } __packed;
  
  /*
   * For directory operations
   */
  #define F2FS_DOT_HASH		0
  #define F2FS_DDOT_HASH		F2FS_DOT_HASH
  #define F2FS_MAX_HASH		(~((0x3ULL) << 62))
  #define F2FS_HASH_COL_BIT	((0x1ULL) << 63)
  
  typedef __le32	f2fs_hash_t;
  
  /* One directory entry slot covers 8bytes-long file name */
  #define F2FS_SLOT_LEN		8
  #define F2FS_SLOT_LEN_BITS	3
  
  #define GET_DENTRY_SLOTS(x)	((x + F2FS_SLOT_LEN - 1) >> F2FS_SLOT_LEN_BITS)
  
  /* the number of dentry in a block */
  #define NR_DENTRY_IN_BLOCK	214
  
  /* MAX level for dir lookup */
  #define MAX_DIR_HASH_DEPTH	63
  
  #define SIZE_OF_DIR_ENTRY	11	/* by byte */
  #define SIZE_OF_DENTRY_BITMAP	((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
  					BITS_PER_BYTE)
  #define SIZE_OF_RESERVED	(PAGE_SIZE - ((SIZE_OF_DIR_ENTRY + \
  				F2FS_SLOT_LEN) * \
  				NR_DENTRY_IN_BLOCK + SIZE_OF_DENTRY_BITMAP))
  
  /* One directory entry slot representing F2FS_SLOT_LEN-sized file name */
  struct f2fs_dir_entry {
  	__le32 hash_code;	/* hash code of file name */
  	__le32 ino;		/* inode number */
  	__le16 name_len;	/* lengh of file name */
  	__u8 file_type;		/* file type */
  } __packed;
  
  /* 4KB-sized directory entry block */
  struct f2fs_dentry_block {
  	/* validity bitmap for directory entries in each block */
  	__u8 dentry_bitmap[SIZE_OF_DENTRY_BITMAP];
  	__u8 reserved[SIZE_OF_RESERVED];
  	struct f2fs_dir_entry dentry[NR_DENTRY_IN_BLOCK];
  	__u8 filename[NR_DENTRY_IN_BLOCK][F2FS_SLOT_LEN];
  } __packed;
  
  /* file types used in inode_info->flags */
  enum {
  	F2FS_FT_UNKNOWN,
  	F2FS_FT_REG_FILE,
  	F2FS_FT_DIR,
  	F2FS_FT_CHRDEV,
  	F2FS_FT_BLKDEV,
  	F2FS_FT_FIFO,
  	F2FS_FT_SOCK,
  	F2FS_FT_SYMLINK,
  	F2FS_FT_MAX
  };
  
  #endif  /* _LINUX_F2FS_FS_H */